Composite parts, such as those made from Carbon Fiber Reinforced Polymer (CFRP), combine high levels of mechanical strength with low weight. This combination is desirable in the field of aircraft design and manufacture. The manufacture of a composite part involves laying up constituent material in layers to form a laminate. The constituent material may comprise a tape that includes parallel carbon fibers pre-impregnated with curable resin. Such pre-impregnated tape is also referred to as “pre-preg” tape. AFP machines may be utilized in order to predictably and reliably lay up pre-preg tape in an automated fashion based on a Numerical Control (NC) program. The resulting laminate is then cured in order to harden into a composite part.
Many desired shapes for composite parts are complex and three dimensional (3D). While AFP machines are capable of laying up complex 3D shapes, the speed of operation of an AFP machine, especially when laying up sharp corners, is substantially reduced. Hence, the amount of machine time (and therefore expense) involved in laying up complex 3D laminates is substantially higher than for flat laminates (e.g., laminates which are largely planar in shape, and which have a height less than a tenth that of their width and/or length). Furthermore, it may be particularly difficult to maintain a laminate in a 3D shape before the laminate has been cured.
Designers of composite parts may utilize AFP machines to lay up flat laminates for curing into flat composite parts, but flat laminates fail to capture any complex surface geometries desired for a composite part (e.g., ensuring an aerodynamic shape). Furthermore, it is not feasible to form flat laminates into complex 3D shapes. This is because carbon fiber within a flat laminate is highly resistant to stretching. Hence, wrinkles may form in the resulting shape as the flat laminate is formed (e.g., molded).
Thus, designers of composite parts continue to seek out techniques for forming a complex contoured part out of flat material without generating wrinkles.